Omicron2 Centauri (ο2 Cen, ο2 Centauri) is a star in the constellation Centaurus.
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 11h 31m 48.79955s[1] |
| Declination | −59° 30′ 56.3296″[1] |
| Apparent magnitude (V) | +5.14[2] (5.12 - 5.22[3]) |
| Characteristics | |
| Evolutionary stage | Blue supergiant |
| Spectral type | A2Iae[3] |
| U−B color index | −0.11[2] |
| B−V color index | +0.49[2] |
| Variable type | α Cyg[3] |
| Astrometry | |
| Radial velocity (Rv) | −16.8[4] km/s |
| Proper motion (μ) | RA: −6.976[1] mas/yr Dec.: +1.118[1] mas/yr |
| Parallax (π) | 0.4665 ± 0.0713 mas[1] |
| Distance | approx. 7,000 ly (approx. 2,100 pc) |
| Absolute magnitude (MV) | −7.50[5] |
| Details[5] | |
| Mass | 18 M☉ |
| Radius | 131 R☉ |
| Luminosity | 105,000 L☉ |
| Surface gravity (log g) | 1.46 cgs |
| Temperature | 9,080 K |
| Rotation | 132 days |
| Rotational velocity (v sin i) | 50 km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
ο2 Centauri is a white A-type blue supergiant with a mean apparent magnitude of +5.12. It is approximately 7,000 light years from Earth. It is classified as an Alpha Cygni type variable star and its brightness varies from magnitude +5.12 to +5.22 with a period of 46.3 days.
In 1996, Kaufer and colleagues calculated Omicron2 Centauri to be around 136,000 times as luminous, 18 times as massive and have 131 times the diameter of the Sun.[5]
ο2 Cen forms a close naked eye pair with ο1 Cen, another 5th magnitude supergiant (possibly a yellow hypergiant). Both stars are located between Crux (the Southern Cross) and the brightest yellow hypergiant in the sky, V382 Carinae.
References
edit- ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
- ^ a b c Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
- ^ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington. Bibcode:1953GCRV..C......0W.
- ^ a b c Kaufer, A.; Stahl, O.; Wolf, B.; Gaeng, T.; Gummersbach, C. A.; Kovacs, J.; Mandel, H.; Szeifert, T. (1996). "Long-term spectroscopic monitoring of BA-type supergiants. I. Halpha_ line-profile variability". Astronomy and Astrophysics. 305: 887–901. Bibcode:1996A&A...305..887K.